speak of a Cato before the Censor, but Pomponius wrote in paragraphs, devoting one to each succession of jurists, and the word Deinde commences that of the Catos, though the Censor had been mentioned by anticipation at the end of the preceding paragraph. From the Catos, father and son, the subsequent jurists traced their succession. Apollinaris Sulpicius, in that passage of Aulus Gellius which is the principal authority with respect to the genealogy of the Cato family, speaks of the son as having written “egregios de juris disciplina libros”. Festus (under Mundus) cites the commentarii juris civilis of Cato, probably the son, and Julius Paullus cites Cato's 15th book. Cicero censures Cato and Brutus for introducing in their published responsa the names of the persons who consulted them. Celsus cites an opinion of Cato concerning the intercalary month, and the regula or sententia Catoniana is frequently mentioned in the Digest. The regula Catoniana was a celebrated rule of Roman law to the effect, that a legacy should never be valid unless it would have been valid if the testator had died immediately after he had made his will. This rule (which had several exceptions) was a particular case of a more general maxim: “Quod initio non valet, id tractu temporis non potest convalescere”. The greater celebrity of the son as a jurist, and the language of the citations from Cato, render it likely that the son is the Cato of the Digest. From the manner in which Cato is mentioned in the Institutes,—“Apud Catonem bene scriptum refert antiquitas,”—it may be inferred, that he was known only at second hand in the time of Justinian. He died when praetor designatus, about 152 BC, a few years before his father, who bore his loss with resignation, and, on the ground of poverty, gave him a frugal funeral. His elder son was the consul of 118 BC, Marcus Porcius Cato. Family Notes References Gregori Maians i Císcar (Gregorius Majansius), ad XXX Iurisconsultus (Comments on thirty jurists), i. I—113. E. L. Harnier, de Regula Catoniana, Heidelb. 1820. Wilhelm Drumann, Geschichte Roms (History of Rome), v. p. 149, 6 Bde. Königsberg 1834–1844. Graham Vincent Sumner, The Orators in Cicero's Brutus: Prosopography and Chronology, (Phoenix Supplementary Volume XI.), Toronto and Buffalo, University of Toronto Press, 1973. This entry incorporates public domain text originally from: William Smith (ed.), A New Classical Dictionary of Greek and Roman Biography,